1. Field of the Invention
The present invention relates to a windmill consisting of a freely rotatable revolution shaft, a plurality of pairs of pivotal support rods provided at the revolution shaft, and wind receiving blades respectively and rotatably set between the pivotal support rods with wind receiving blade shafts. The windmill is applied to the driving of a lifting pump, a generator and the like by employing revolution driving force.
2. Prior Art
As windmills of this type, there have been hitherto known those disclosed by, for example, Japanese Patent Unexamined Application Publication Nos. 55-131585, 57-372, 57-56674 and 11-117850.
Japanese Patent Unexamined Application Publication No. 55-131585 discloses the structure of a windmill which consists of a plurality of blades rotating on their own shafts and revolving around a revolution main shaft, gears provided at the rotary shafts of these blades, respectively and gears provided at the main shaft of the windmill. The gears are coupled to one another by planetary gears or chains.
Japanese Patent Unexamined Application Publication No. 57-372 discloses the structure of a windmill which consists of a pair of wind receiving blades provided symmetrically, rotatably around a revolution main shaft, rotation shafts extending from the central positions on the lower ends of the wind receiving blades, respectively, gears provided at the rotation shafts, respectively, a gear provided on the lower portion of the revolution main shaft and a rudder provided at the gear. The former and latter gears are mutually coupled by a timing belt.
Japanese Patent Unexamined Application Publication No. 57-56674 discloses a windmill wherein a plurality of planetary shafts are revolvably provided around a solar shaft, blades are attached to the plurality of planetary shafts at different angles, respectively, a locking mechanism associated with the solar shaft so as to allow the plurality of planetary shafts to rotate half in the same direction as the revolution direction per revolution is provided, and the revolution forces of the planetary shafts are taken out as outputs.
Further, Japanese Patent Unexamined Application Publication No. 11-117850 discloses a windmill consisting of a rotatable revolution shaft, a plurality of pairs of pivotal support rods provided at the revolution shaft, planetary shaft frames rotatably provided at the pivotal support rods through planetary shafts, respectively and each having a wind receiving means, planetary shaft bevel gears formed on the lower end portions of the respective planetary shafts and a wind direction bevel gear provided on the lower end portion of the revolution shaft. It particularly discloses that a windmill can be made larger in size and can output high power by employing, as the coupling means, a bevel gear shaft having bevel gears on both ends thereof, respectively.
In each of these conventional windmills, however, a plurality of wind receiving blades which rotate and revolve are mechanically coupled to the revolution shaft. Due to this, the rotation of the wind receiving blades is specified univocally based on their mechanical coupling states and the setting of the rotating positions of the wind receiving blades has been quite restricted.
In recent years, environmental issues are highlighted. In this connection, the reduction of vibration and noise is regarded as a challenge for the windmills. It is, therefore, desired that a windmill itself has a simple structure and mechanical parts thereof such as gears are as simple as possible.
Further, according to each of the conventional windmills, a wind receiving blade is formed as a mechanism rotating through gears or the like. This inevitably leads to a larger windmill and more complex mechanisms.
It is an object of the present invention to overcome the above-stated disadvantages and to realize a highly reliable windmill with the windmill itself having a simple structure.
It is another object of the present invention to provide highly efficient wind receiving blades control by rotating the wind receiving blades in directions most efficient for receiving wind, freely positioning the rotation of the wind receiving blades irrespectively of the revolution of the revolution shaft and allowing the wind receiving blades to freely invert and stop.
The present invention has overcome the above disadvantages by a windmill and a windmill control method described below.
(1) A windmill comprising a rotatable revolution shaft; a plurality of pairs of upper and lower pivotal support rods provided around the revolution shaft; wind receiving blades put between the pairs of pivotal support rods and also respectively and rotatably set between the pairs of pivotal support rods with wind receiving blade shafts; servo motors directly coupled to the wind receiving blade shafts, for freely positioning directions of the wind receiving blades, respectively; wind receiving blade rotating position detectors for detecting rotating positions of the wind receiving blade shafts respectively; revolution shaft revolving position detector for detecting revolving position of the revolution shaft; an anemometer/anemoscope measuring a wind velocity and a wind direction; and a servo motor control section to be input the wind direction and the wind velocity measured by the anemometer/anemoscope and to be input the revolving position of the revolution shaft and then controlling the servo motors to thereby control directions of the wind receiving blades.
(4) A windmill control method in a steady state of controlling directions of wind receiving blades of a windmill consisting of a rotatable revolution shaft, a plurality of pairs of pivotal support rods provided at the revolution shaft and the wind receiving blades respectively and rotatably set between the pairs of pivotal support rods with wind receiving blade shafts by inputting a wind direction and a wind velocity measured by an anemometer/anemoscope and a revolving position of the revolution shaft of the windmill, and also characterized in that an upwind point on a revolution circumference on which the wind receiving blades revolve counterclockwise is set at point C, a point at 90xc2x0 clockwise from the point C on the revolution circumference is set at point A, and points at 45xc2x0 intervals from the point A are defined as points B, C and D to thereby define all points on the revolution circumference, with the final point set at a point H, and directions of the wind receiving blades are controlled so that the directions of the wind receiving blades at the point A are parallel to the wind direction, while the windmill revolves once, the wind receiving blades rotate clockwise by a {fraction (1/24)} turn at the points A to C, the wind receiving blades rotate counterclockwise by a {fraction (1/12)} turn at the points C to G, and the wind receiving blades rotate clockwise by a {fraction (1/24)} turn at the points G to A.
(5) A windmill control method in a strong wind state of controlling directions of wind receiving blades of a windmill consisting of a rotatable revolution shaft, a plurality of pairs of pivotal support rods provided at the revolution shaft, a plurality of pairs of pivotal support rods provided at the revolution shaft and the wind receiving blades respectively and rotatably set between the pairs of pivotal support rods with wind receiving blade shafts, by inputting a wind direction and a wind velocity measured by an anemometer/anemoscope and a revolving position of the revolution shaft of the windmill, and also characterized in that an upwind point on a revolution circumference on which the wind receiving blades revolve counterclockwise is set at point C, a point at 90xc2x0 clockwise from the point C on the revolution circumference is set at point A, and points at 45xc2x0 intervals from the point A are defined as points B, C and D to thereby define all points on the revolution circumference, with the final point set at a point H, and directions of the wind receiving blades are controlled so that the direction of the wind receiving blades at the point A are parallel to the wind direction, and that while the windmill revolves once, the wind receiving blades rotate clockwise by a {fraction (5/24)} turn at the points A to C, the wind receiving blades rotate clockwise by a {fraction (7/12)} turn at the points C to G, and the wind receiving blades rotate clockwise by a {fraction (5/24)} turn at the points G to A.
(6) A windmill control method in an emergency state such as a gale wind of controlling directions of wind receiving blades of a windmill consisting of a rotatable revolution shaft, a plurality of pairs of pivotal support rods provided at the revolution shaft and the wind receiving blades respectively and rotatably set between the pairs of pivotal support rods with wind receiving blade shafts, by inputting a wind direction and a wind velocity measured by an anemometer/anemoscope and a rotating position of the revolution shaft of the windmill, and also characterized in that a point at 90xc2x0 clockwise from an upwind point on a revolution circumference on which the wind receiving blades revolve counterclockwise is set at a reference point, and the windmill is controlled so that direction of the wind receiving blades at the reference point is parallel to the wind direction; and the wind receiving blades rotate once clockwise while the windmill revolves once.